No Arabic abstract
In this article, we focus on the left translation actions on noncommutative compact connected Lie groups with topological dimension 3 or 4, consisting of ${rm SU}(2),,{rm U}(2),,{rm SO}(3),,{rm SO}(3) times S^1$ and ${{rm Spin}}^{mathbb{C}}(3)$. We define the rotation vectors (numbers) of the left actions induced by the elements in the maximal tori of these groups, and utilize rotation vectors (numbers) to give the topologically conjugate classification of the left actions. Algebraic conjugacy and smooth conjugacy are also considered. As a by-product, we show that for any homeomorphism $f:L(p, -1)times S^1rightarrow L(p, -1)times S^1$, the induced isomorphism $(picirc fcirc i)_*$ maps each element in the fundamental group of $L(p, -1)$ to itself or its inverse, where $i:L(p,-1)rightarrow L(p, -1)times S^1$ is the natural inclusion and $pi:L(p, -1)times S^1rightarrow L(p, -1)$ is the projection.
Let $G$ be connected nilpotent Lie group acting locally on a real surface $M$. Let $varphi$ be the local flow on $M$ induced by a $1$-parameter subgroup. Assume $K$ is a compact set of fixed points of $varphi$ and $U$ is a neighborhood of $K$ containing no other fixed points. Theorem: If the Dold fixed-point index of $varphi_t|U$ is nonzero for sufficiently small $t>0$, then ${rm Fix} (G) cap K e emptyset$.
In this work we obtain the general form of polynomial mappings that commute with a linear action of a relative symmetry group. The aim is to give results for relative equivariant polynomials that correspond to the results for relative invariants obtained in a previous paper [P.H. Baptistelli, M. Manoel (2013) Invariants and relative invariants under compact Lie groups, J. Pure Appl. Algebra 217, 2213{2220]. We present an algorithm to compute generators for relative equivariant submodules from the invariant theory applied to the subgroup formed only by the symmetries. The same method provides, as a particular case, generators for equivariants under the whole group from the knowledge of equivariant generators by a smaller subgroup, which is normal of finite index.
We use a tensor C*-category with conjugates and two quasitensor functors into the category of Hilbert spaces to define a *-algebra depending functorially on this data. If one of them is tensorial, we can complete in the maximal C*-norm. A particular case of this construction allows us to begin with solutions of the conjugate equations and associate ergodic actions of quantum groups on the C*-algebra in question. The quantum groups involved are A_u(Q) and B_u(Q).
This paper presents algebraic methods for the study of polynomial relative invariants, when the group G formed by the symmetries and relative symmetries is a compact Lie group. We deal with the case when the subgroup H of symmetries is normal in G with index m, m greater or equal to 2. For this, we develop the invariant theory of compact Lie groups acting on complex vector spaces. This is the starting point for the study of relative invariants and the computation of their generators. We first obtain the space of the invariants under the subgroup $H$ of $Gamma$ as a direct sum of $m$ submodules over the ring of invariants under the whole group. Then, based on this decomposition, we construct a Hilbert basis of the ring of G-invariants from a Hilbert basis of the ring of H-invariants. In both results the knowledge of the relative Reynolds operators defined on H-invariants is shown to be an essential tool to obtain the invariants under the whole group. The theory is illustrated with some examples.
In this report, we first recall the Poincares classification theorem for minimal orientation-preserving homeomorphisms on the circle and the Ghys classification theorem for minimal orientation-preserving group actions on the circle. Then we introduce a classification theorem for a specified class of topologically transitive orientation-preserving group actions on the circle by $mathbb Z^d$. Also, some groups that admit/admit no topologically transitive actions on the line are determined.